1. Field of the Invention
The present invention relates to a vehicular lamp which is attached to a vehicle body by means of a pin projecting from a back surface of a lamp body. More particularly, the invention relates to a vehicular lamp in which the pin is integrally formed with the lamp body.
2. Related Art
Generally in conventional vehicular lamps, various kinds of fixing means such as a stack bolt, tapping screw or the like have been used for attaching and fixing lamps to vehicle body. Recently, pin device has become trendy as the fixing means. In this structure, a pin, which is integrally formed with a lamp body, projects from a back surface of the lamp body, and the pin snap-fits into a fastener which is previously attached to the vehicle body, so that the lamp body is attached to the vehicle body.
Generally, the conventional pin has a rod a tip end of which is ball-shaped or spindle-shaped. In a case where the lamp body is molded by resin material, the pin is integrally molded with the lamp body. On the other hand, the fastener is formed with a cylindrical body having a snap structure in which the tip end of the pin is inserted into the cylindrical body while it is resiliently deformed. More specifically, the fastener mounts to a fastener mounting hole formed on the vehicle body, and when the tip end of the pin is inserted into the fastener, the cylindrical body is resiliently deformed due to slits to thereby enlarge a diameter thereof. Thereafter, when the pin is further inserted and the head of the pin passes over the cylindrical body, the cylindrical body returns to have the original diameter, so that the tip end of the pin is held.
In the vehicular lamp employing the pin device thus provided, before attaching the lamp to the vehicle body, because the pin projecting from the back surface of the lamp body is exposed to the outside, the pin may be easily damaged or broken upon external forces applied thereto. Further, when the lamp is attached to the vehicle body during assembly, the pin may be easily bent or damaged due to irregular force caused by the force applied to the lamp.
In order to avoid such a problem, the pin has been required to be thicker or shorter. However, the length of the pin is not freely designed but forcively determined in consideration of the distance between the lamp body and the vehicle body. For this reason, the pin could only be thickened to reinforce the mechanical strength thereof. However, if the pin is designed to be thicker, the resin thickness of lamp body at the portion where the pin projects must be enlarged, which causes another problem. That is, during the resin molding process, the time required for cooling down and solidifying the molten resin at the portion where the pin projects must be longer than the other portions of the lamp body. As a result, the surface would easily sink to create a dent, which phenomena is so called as a "shrinkage". Because the shrinkage appears on a surface opposite to the pin, the undesirable dent is generated on an inner surface of the lamp body, that is, a reflective surface of the lamp, so that the light reflection characteristics of the lamp would be deteriorated.